X-Git-Url: https://wannabe.guru.org/gitweb/?a=blobdiff_plain;ds=sidebyside;f=list_utils.py;h=1141af2fe9b6bb8861dfd25c08dab735bfd4ceaf;hb=a9bdfd8fc9f84b7b2c09a57cd12ba32259e84d1c;hp=91af8f9eb924fb7e7e04932d58a1bcb6eded0690;hpb=e8fbbb7306430478dec55d2c963eed116d8330cc;p=python_utils.git

diff --git a/list_utils.py b/list_utils.py
index 91af8f9..1141af2 100644
--- a/list_utils.py
+++ b/list_utils.py
@@ -1,10 +1,13 @@
 #!/usr/bin/env python3
 
+# © Copyright 2021-2022, Scott Gasch
+
 """Some useful(?) utilities for dealing with Lists."""
 
+import random
 from collections import Counter
-from itertools import islice
-from typing import Any, Iterator, List, Sequence, Tuple
+from itertools import chain, combinations, islice
+from typing import Any, Iterator, List, MutableSequence, Sequence, Tuple
 
 
 def shard(lst: List[Any], size: int) -> Iterator[Any]:
@@ -232,6 +235,30 @@ def _permute(seq: str, path: str):
         yield from _permute(cdr, path + car)
 
 
+def shuffle(seq: MutableSequence[Any]) -> MutableSequence[Any]:
+    """Shuffles a sequence into a random order.
+
+    >>> random.seed(22)
+    >>> shuffle([1, 2, 3, 4, 5])
+    [3, 4, 1, 5, 2]
+
+    >>> shuffle('example')
+    'empaelx'
+
+    """
+    if isinstance(seq, str):
+        import string_utils
+
+        return string_utils.shuffle(seq)
+    else:
+        random.shuffle(seq)
+        return seq
+
+
+def scramble(seq: MutableSequence[Any]) -> MutableSequence[Any]:
+    return shuffle(seq)
+
+
 def binary_search(lst: Sequence[Any], target: Any, *, sanity_check=False) -> Tuple[bool, int]:
     """Performs a binary search on lst (which must already be sorted).
     Returns a Tuple composed of a bool which indicates whether the
@@ -280,6 +307,23 @@ def _binary_search(lst: Sequence[Any], target: Any, low: int, high: int) -> Tupl
         return (False, low)
 
 
+def powerset(lst: Sequence[Any]) -> Iterator[Sequence[Any]]:
+    """Returns the powerset of the items in the input sequence.
+
+    >>> for x in powerset([1, 2, 3]):
+    ...     print(x)
+    ()
+    (1,)
+    (2,)
+    (3,)
+    (1, 2)
+    (1, 3)
+    (2, 3)
+    (1, 2, 3)
+    """
+    return chain.from_iterable(combinations(lst, r) for r in range(len(lst) + 1))
+
+
 if __name__ == '__main__':
     import doctest